Blanket system for temperature regulation of a patient

ABSTRACT

A blanket system ( 1 ) is provided for maintaining or controlling a patient&#39;s body temperature before, during, or after surgical and non-surgical procedures. The system includes a non-obtrusive cover blanket ( 3 ), a blower ( 28 ) to blow the air beneath the blanket ( 3 ) and a vacuum source ( 30 ) to suction the air from beneath the blanket ( 3 ) and away from the patient.

This application claims the benefit of Provisional Application No.60/174,944 filed Jan. 7, 2000.

FIELD OF THE INVENTION

This invention generally relates to a thermal blanket and morespecifically to a device and method for regulating the body temperatureof a patient.

BACKGROUND OF THE INVENTION

The control of body temperature of patients is particularly a concernbefore, during and after surgical operations because an abnormaltemperature may affect the stability of the patient under anesthesia aswell as the patient's recovery. One significant issue concerning thecontrol of the patient's body temperature is hypothermia. Hypothermia inturn leads to complications during and after surgery including: thermaldiscomfort, impairment of the blood's ability to coagulate, impairedresponse by the body to wound infections and in serious situations evencongestive heart failure, respiratory failure, or stroke. Loss of heatfrom the patient can be caused by a variety of factors including: thelow temperature of the operating room, lack of insulating clothing onthe patient, preparation of the patient's skin using cold or volatilesolutions, and losses from incisions made upon the patient. The problemis compounded by the increased difficulty of the patient's body tothermoregulate itself during an operation because of the effects ofanesthesia. The restoration of normal body temperature is also a concernfor patients suffering from hypothermia due to overexposure to coldconditions unrelated to surgery. Thus it is important to warm up thepatient as quickly as possible. Conversely, patients who arehyperthermic may require medical intervention to reduce their bodytemperature to prevent damage to internal organs.

Many solutions have been proposed to minimize heat loss from patients.Some include introducing heat to the patient from an outside source suchas the application of pre-warmed hospital blankets. This is aninexpensive, simple solution, but has the disadvantage in that theblankets are merely insulators and the heat introduced by prewarming isquickly dissipated. Blankets which have heated water circulatingthroughout have also been used with some degree of success. Theseblankets have an outside source of heat, but are generally heavy andbulky due to the fluid's weight. Water blankets can also be unsanitarybecause they are used repeatedly and have a tendency to leak over time.

Another prior art approach to controlling the patient's body temperatureis to increase the operating room temperature or at least the areaaround the patient using heat lamps. This method has the drawback ofoverheating of the surgical team which is generally heavily clothedalready.

Another approach to regulating patient temperature is throughutilization of air circulating blankets and cushions which provide anoutside source of heat. One disadvantage of this approach is that dualwalled blankets which have an interior chamber for air passage are aphysical obstruction due to their inherent thickness. When air issupplied to the blanket, the blanket “puffs up” and may interfere withsurgery. If the interior chamber is instead a series of passages, it isdifficult to reduce the overall size of the blanket or cut access holesinto it without eliminating air flow within an entire passage. Also,prior art air circulating blankets or blanket systems exhaust the heatedair around the patient, which then results in overheating the surgicalteam.

A system having the ability to supply air which will warm or cool apatient and the ability to suction air away from the area around thepatient, and which is not obtrusive is desired.

SUMMARY OF THE INVENTION

The present invention overcomes these and other disadvantages of theprior art by providing a system which uses a thin, non-obtrusive coverblanket underneath which, air is introduced. The invention provides inone aspect, a surgical blanket system for regulating a patient'stemperature comprising a blanket, a source of air including a blowerwhich blows said air beneath said blanket at a first end, and a vacuumsource which suctions said air from beneath said blanket at a secondend.

The invention provides in another aspect a device for regulating apatient's temperature comprising a support cushion having upper andlower spaced surfaces which define an interior chamber containing heatretaining material, said upper surface having one or more holes, and asource of air, connected to an inlet of said interior chamber.

The invention provides in yet another aspect a surgical blanket systemfor regulating a patient's temperature comprising a blanket, a source ofair including a blower which blows said air beneath said blanket at afirst end, and a vacuum source which suctions said air from beneath saidblanket at a second end, as well as a support cushion having upper andlower spaced surfaces which define an interior chamber containing heatretaining material, said upper surface having one or more holes, and asource of air connected to an inlet of said interior chamber.

The invention provides in yet another aspect a method for controllingthe temperature of a patient comprising the steps of: covering a portionof the patient with a blanket, forcing air from an air source beneathsaid blanket using a blower, and suctioning air from underneath saidblanket using a vacuum source.

These and other aspects of the invention are herein described inparticularized detail with reference to the accompanying Figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a top view of a blanket system with a patient lying on anoperating table beneath the cover blanket;

FIG. 2 is a side view of the cover blanket covering a patient lying uponan operating table;

FIG. 3 is a perspective view of the source of air;

FIG. 4 is a perspective view of the support cushion;

FIG. 5 is a side view of a patient lying upon the support cushion;

FIG. 6 is a top view of a patient lying upon the support cushion;

FIG. 7 is a top view of the blanket system being used in conjunctionwith the support cushion;

FIG. 8 is a side view of the blanket system being used in conjunctionwith the support cushion;

FIG. 9 is a top view of a modified blanket system where sections of theblanket have been removed to allow surgical access to the lower body;

FIG. 10 is a side view of a modified blanket system where sections ofthe blanket have been removed to allow surgical access to the lowerbody;

FIG. 11 is a top view of a modified blanket system where sections of theblanket have been removed to allow surgical access to the upper body;

FIG. 12 is a side view of a modified blanket system where sections ofthe blanket have been removed to allow surgical access to the upperbody;

FIG. 13 is a top view of a modified blanket system where sections of theblanket have been removed to allow surgical access to a single leg;

FIG. 14 is a side view of a modified blanket system where sections ofthe blanket have been removed to allow surgical access to a single leg;

FIG. 15 is a top view of a modified blanket system where a hole has beencut out of the cover blanket and the blanket sealed to the patient'sbody to allow surgical access to the center of the body and

FIG. 16 is a top view of a modified blanket system where a hole has beencut out of the cover blanket and the blanket sealed to the patient'sbody to allow surgical access to the center of the body.

DETAILED DESCRIPTION OF PREFERRED AND ALTERNATE EMBODIMENTS

Referring to the drawings, FIG. 1 illustrates a preferred blanket system1 according to the invention. This blanket system 1 may be used toregulate the temperature of a patient for example, before, during andafter surgery. Alternatively, the system may be used in non-surgicalsituations where it is necessary to raise or lower a patient'stemperature. The blanket system, as described in more detail below,comprises a cover blanket 3, a source of air 20, and a vacuum source 30to suction and exhaust the air from under the blanket 3 after it haspassed over the patient. Either warmed, cooled or room temperature airmay be supplied from the source of air 20 depending upon the requiredtreatment to the patient. The cover blanket 3 is preferably sized so itfits over a patient's chest, torso, legs and feet. Alternatively, thesize of the blanket may be reduced to cover only a portion or portionsof the body. FIGS. 9-16 show variations in the size of the cover blanket3, for example covering a patient's body from the feet to the torso orfrom the patients neck to the torso. Cover blanket 3 is of sufficientwidth to completely cover the patient. The cover blanket 3 is preferablymade of paper which may be disposed of after each use. Alternatively,the blanket may be made of cloth or plastic or any other material whichresults in a blanket which is thin, non-obtrusive and preferablyinexpensive.

Cover blanket 3 is preferably equipped with double sided tape 5 toattach it to another surface, such as an operating table. Instead oftape, other attachment means may be used such as two part cloth adheringstrip systems, an adhesive strip, or other means known to those skilledin the art. The tape 5 is placed along the outside perimeter of theblanket 3. Preferably, the tape 5 is applied to the blanket in such away as to allow an air tight seal to be formed between blanket 3 and alower surface. Cover blanket 3 may be attached directly to the patientusing tape or other adhesive in areas of the perimeter which do notcontact the operating table. Cover blanket 3 may preferably comprise oneor more horizontal or vertical seams 7 which are created by aperforation process. These seams allow for quick removal of a part ofthe blanket 3 when a smaller blanket is preferred. For example, reducedsize may be required when the surgery is to take place on a lower partof the body as shown in FIG. 9. Cover blanket may also be cut using aknife or scissors when small areas of the body must be exposed as shownin FIG. 15. Preferably the perimeter of any cut area still be secured tothe body or the lower surface using tape 5 in order to keep the airbeneath the cover blanket 3.

Blanket system 1 further includes a source of air 20 which comprises ablower 28 and is used in conjunction with an inlet port 9 and diffuser11, an air supply duct 13, and a heating and/or cooling element 22. Theelement 22 heats air from the source of air 20 when room temperature airis insufficient to warm the patient. The element 22 cools the air fromthe source of air 20 when room temperature is insufficient to cool thepatient. An inlet port 9 allows air to be blows beneath the coverblanket 3. A diffuser 11 is preferably integrally formed with the inletport 9, but may also be a separate connected piece. Diffuser 11 is usedto spread air evenly along the width of the blanket. While any size orshape of the diffuser 11 may be utilized, it is preferred that thediffuser 11 is elongated and rectangular shaped, having multipledischarge ports which allow an equal amount of air to exit along itslength. Preferably, the diffuser 11 is positioned close to the edge ofcover blanket 3 near the patient's head. Alternatively, placement may bein the chest or torso region. Air is brought to the inlet port 9 anddiffuser 11 via an air duct 13 which is connected to the inlet port 9 aswell as a source of air 20.

Referring to FIG. 3, a system to blow air is shown. Air source 20comprises a blower 28 to transfer air through air duct 13. Preferably,the blower and the heating/cooling element 22 are held within case 26.Preferably the heating/cooling element 22 are sized to generate aconstant supply of air in a temperature range of about 35 to 45 degreesCentigrade. Depending upon the size of heating/cooling element 22, andblower 28, these elements may be aligned side by side or in line withincase 26, but are not limited to these positions.

In an embodiment including healing/cooling element 22, preferably atemperature control system 24 is used to maintain the air within apreset temperature range. The temperature control system 24 includes oneor more temperature sensors 40 as shown in FIG. 1. The temperaturesensor 40 may be a thermocouple or other type of sensor known to thoseskilled in the art. The temperature sensor 40 may be utilized to monitorthe temperature of the patient at various places, and the inlet airstream temperature near the patient. The control system also includes adial or other device 25 known to those skilled in the art where adesired temperature range can be set. The control system is connectingto the heating/cooling element 22, and the blower to cycle the elementsand blower in order to achieve a temperature in the range of about 35 to45 degrees Centigrade. Temperature sensor 40 may be used in a system notutilizing a heating/cooling element 22 to simply monitor airtemperature.

The blanket system 1 further comprises a vacuum source 30 to suction airfrom beneath the cover blanket 3. Vacuum source 30 may be a blower orother device known in the art which creates suction. FIGS. 1 and 2 showa suction port 15 placed in an area preferably distant from the diffuser11. Preferably suction port 15 is a fixture, made of an inexpensivematerial attached around a hole 16 in blanket 3. However, suction port15 may be the same element as air duct 17 which is a simple tube orother type of air duct and is placed through blanket 3 or betweenblanket 3 and the surgical table with blanket 3 being taped to the tube.This port allows air which has passed across the body of the patient tobe exhausted to an area away, from the surgical staff. Thus the staff isnot inconvenienced by extra heat or air motion and this is an advantagethat did not exist in the prior art. If suction port 15 is not the sameelement as air duct 17, suction port 15 is connected to air duct 17.Suction is created within air duct 17 by use of a vacuum source 30 withthe intake end preferably being sealed to the air duct 17. Preferablythe flowrate of the vacuum source 30 is about the same as the flowrateof air blower 28. Preferably, exhaust air may be used as supply air forblower 28. This increases energy efficiency in systems utilizing aheating/cooling element 22. As shown in FIG. 7 auxiliary air duct 18 mayroute air to blower 28, heating/cooling element 22. Alternatively,exhaust air may be dumped to an area away from the surgical staff.

The operation of the system may now be described. In an embodiment usingeither heating/cooling element 22, supply air from the generalsurroundings is suctioned into the inlet side of heating/cooling element22. Supply, air passes through heating/cooling element 22. This supplyair, now in the desired temperature range, passes into the inlet side 27of the blower 28. In an embodiment without heating/cooling element 22,supply air is suctioned directly into the inlet side 27 of blower 28.Supply air then passes through the outlet side 29 of the blower and intoair duct 13. After passing through the air duct 13, the air reaches thediffuser 11 and is discharged across the body of the patient. As itreaches the lower end of the patient the air is sucked away through thesuction port 15, through air duct 17, to the vacuum source 30.Preferably, the air from vacuum source 30 is routed back throughauxiliary duct 17 to the heating/cooling element 22 or blower 28.Alternatively the air is discharged in an area away from the surgicalteam.

In an alternate embodiment of the invention, a support cushion 50 isshows in FIG. 4. The support cushion 50 may be used alone or inconjunction with the blanket system 1. Support cushion 50 is sized andshaped for placement upon a common operating table and configured forplacement underneath a patient. As shows in FIG. 4, cushion 50 has anupper surface 52 and a lower surface 54 which are spaced apart creatinga chamber within. Preferably, a portion of the upper surface 52 has oneor more channels 56 oriented lengthwise. Channels 56 allow for greaterheat transfer by convection of the air through the cushion 50 and to thepatient. Further, channels 56 create a place for fluids to pool so thatthey do not contact the patient. Preferably the perimeter of the uppersurface is smooth thus allowing a cover blanket to be easily attached tothe surface as shown in FIG. 6. Upper surface 52 contains multiple holes70 which allow the passage of air from the cushion chamber to the areasurrounding the patient.

The operation of the support cushion max now be described. Air is blowninto a first end 51 of the cushion 50. Preferably a plenum 58 is used todistribute the air along the entire width of the cushion 50. Plenum 58is shown as a tubular piece extending the entire width of the cushion50, but is not limited to this shape. Plenum 58 includes multiple holes62 from which the air may enter the cushion chamber. One end 57 ofplenum 58 is sealed while the opposite end 59 is open. A source of airma be attached to opposite end 59 of the plenum 58. The source may besimilar to air source 20 or could be the same source if the cushion 50is used in conjunction with the blanket 1. The chamber of cushion 50 isfilled with heat retaining material such as fibers. Preferably, the heatretaining material is beads 65 which may be made of Styrofoam or othermaterial such as plastic so the cushion 50 will retain heat when thesource of air is closed off. Preferably the beads 65 are of a sphericalshape and size, which ill allow air to pass between them even whenpacked tightly together.

Air from within the cushion 50 passes through holes 70 in the uppersurface 52 of the cushion and into the area around the patient. When thecushion 50 is used alone, this air escapes into the surroundings. Whenused in conjunction with blanket system 1, air from the cushion 50 issuctioned from under the cover blanket 3 by vacuum source 30.

The blanket system 1, cushion 50 or combination of both as shown inFIGS. 7 and 8 may be used to regulate a patient's temperature during anoperation before an operation, during recover, and where temperatureregulation of the patient is required. However, the invention is notlimited to the above described uses on the invention.

Although the invention has been shows and described with reference tocertain preferred and alternate embodiments the invention is not limitedto these specific embodiments. Minor variations and insubstantialdifferences in the various combinations of materials and methods ofapplication may occur to those of ordinary, skill in the art whileremaining within the scope of the invention as clamed and equivalents.

What is claimed is:
 1. A surgical blanket system for regulating apatient's temperature comprising: a blanket having oppositely disposedfirst and second ends; a source of air including a blower which blowssaid air beneath said first end of said blanket; and a vacuum sourcewhich suctions said air from beneath said blanket at said second end ofsaid blanket.
 2. The surgical blanket system according to claim 1,wherein said blanket includes double side tape along its perimeter forsealing said perimeter to another surface.
 3. The surgical blanketsystem according to claim 1, further having perforated seams whichdivide said blanket into sections.
 4. The surgical blanket systemaccording to claim 1, further having a temperature control system whichmaintains said air within a range of about 35 to 45 degrees Centigrade.5. The surgical blanket system of claim 1, wherein an outlet end of saidvacuum source is connected to an intake of said blower.
 6. The surgicalblanket system according to claim 1 wherein said air is heated.
 7. Thesurgical blanket system according to claim 1 wherein said air is cooled.8. A surgical blanket system for regulating a patient's temperaturecomprising: a blanket; a source of air including a blower which blowssaid air beneath said blanket; a vacuum source which suctions said airfrom beneath said blanket; and a support cushion having upper and lowerspaced surfaces which define an interior chamber containing a heatretaining material; said upper surface having one or more holes fordirecting airflow over the patient; said source of air also introducingair into said interior chamber.
 9. The surgical blanket system accordingto claim 8 wherein said heat retaining material is spherically shaped.10. The surgical blanket system according to claim 8 wherein said heatretaining material is styrofoam.
 11. A method of controlling thetemperature of a patient comprising the steps of: covering the patientwith a blanket; forcing air from an air source beneath said blanketusing a blower; and suctioning air from underneath said blanket using avacuum source.